There are quite a few words that appearing in the bible that were adopted by the christianized versions of it and these words were transcripted from the Hebrew to Greek and then from the Greek to Latin and from there to the other European languages. Those words eventually lost all connection to their original meaning that is perhaps even unknown to those who use them, such words are:

Amen - (originally pronounced ah-MEHN) a word derived from the root 'a-m-n' indicating faith or belief

Hallelujah/Alleluia - a composite of two words: 'halelu' (pronounced hah-leh-LOO) the imperative, 3rd person, plural of the root h-l-l meaning 'praise' or 'glorify', and 'ia' a short form of the explicit name (the term Jews use for the name YHWH).

Hosanna - originally the words are 'hoshe'a na' meaning: 'please salvage' the 'sh' turned into 's' because the consonent 'sh' ('sch', or 'ch' for the German and French speakers among us) did not exist either in Greek or in Latin.

Sabaoth - originally the word is 'tzeva'ot' meaing 'hosts' or 'armies'

Sabbath - originally 'Shabbat', the name of the 7th day of the Jewish week, Saturday. The name is derived from the root sh-b-t meaning 'to cease working'.

Satan - the root of this word is s-t-n, meaing to snitch (tell on somebody) or to prosecute. In the Jewish perception Satan is not and could not be an adversary of god, because no one can compare with the might of god. and thus the satan is an underling of his, whose job is to test people, prosecute them to god's court, and tell on them. In fact originally the satan is not even a certain angel, but a position that is filled by various angels in different situations (an example is Numbers 22, 22: "...and the angel of the Lord stood in the way for an adversary against him.", in the Hebrew original the sentence goes: "...and the angel of the Lord stood in the way as a satan to him" thus indicating that any angel could be 'satan' when the need arose).

Messiah - originally 'Mashiyach', the word derives from the root m-sh-ch, indicating the applying of ointments or oils. It was customary in Judea to apply sacred oil from the temple on every king's head in his coronation, and that king was later refered to also as Mashiyach. As the Jewish tradition sees the Messiah as king and descendant of kings he is often referred to by this title.

Seraph - 'Saraf' in the original Hebrew, the root s-r-f means 'to burn', and indeed these angels are usually associated with fire. The plural 'Seraphim' is actually the original Hebrew masculine plural (Srafim).

There are many more but that's all I can think of right now, I'll fill in more as I recall them.


Response to scraimer:

While it is true that those initials are used in the interpretation of this word, they are not relevant to the actual meaning of it. In the Middle-Ages (a term that as far as Jewish history and the history of the Hebrew language are concerned defines the period between the 3rd and the 17th centuries CE) many religious terms were interpreted by the use of initials, some of them, one has to say, quite improbable, the interpretaion of 'Amen' as initials is a part of this trend (cf. also 'Sheina Be-shabbat Ta'anug' for Shabbat and Yimach Shemo Ve-zichro for Yeshu, which is in itself an intentional corruption of his origial name: Yeshu'a). These initials are artificial interpretations made by people who knew very little philology.